A Multi-scale Model For Reactive Distillation Process And Simulation

Reactive distillation(RD), as a kind of technology that combine the reactor and distillation column together. Aiming to separate the reactants and product in situ.Compared with the traditional method of reaction and distillation,there are many advantages of RD,such as promoting the conversion of reactant,increasing the productivity,and avoiding the forming of azeotrope,ect.Building a precise model for reactive distillation process is meaningful in production practice and theoretical research.For a reactive distillation column that contains difference scale structures,in this article we build mathematical models that base on the scale of catalyst particles(micro-scale),the scale of catalyst bed(meso-scale) and the scale of the reactive distillation column(macro-scale).By using the many domain strategy,these three models are integrated as a multi-scale model, to describe the reactive distillation process.In older to solve the model,we use MTBE synthesis as an example and the RD column is packed with structured packages KATAPACK-S. The results of equilibrium model and non-equilibrium model are also got by solving the equations of these two model respectively.Then there is a comparison of the results between these three models.The results show that there are some difference between the three models,and the multi-scale model can present more details about the RD process.A shunt factor,that is used to divided the liquid stream to two in the reactive section,one stream flow through the reactive zone,anther stream flow through the liquid-vapor mass transfer zone. By changing the value of the shunt factor,we study the effect of the distribution of liquid flow that pass through the reactive zone and the liquid-vapor mass transfer zone on behavior of the RD column.The value for the shunt factor are 0.5,0.60,0.65,0.70,0.75. The result show that increasing the flow rate of stream that pass through the reactive zone is good for promoting the productivity,but lowing the component of the desired product.A study on the behavior of RD column is performed by changing the diameter of the catalyst particle.The value of catalyst particle are 0.8mm,1.6mm and 2.4mm.The results show that using the larger size of catalyst particle weak the solid-liquid mass transfer process,so the productivity of MTBE is decreased.